Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
On-Board Refueling Vapor Recovery (ORVR) System
ORVR system is used to recover fuel vapors into EVAP canister that are generated during refueling. ORVR system consists of fuel inlet pipe, overfill check valve and EVAP canister.
When fuel tank cap is removed, atmospheric pressure is applied to port "A" on overfill check valve. See Fig 1. Overfill check valve may also be referred to as ORVR-OCKV or fill check valve. When fuel flows into fuel inlet pipe and fuel tank, pressure in fuel tank increases. Increased pressure in fuel tank causes valve "B" on overfill valve to open, allowing fuel vapors to flow into EVAP canister. When fuel tank is full, valve "C" closes, shutting off vapor flow to EVAP canister.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.